How is EMPD Classified?

Extramammary Paget’s disease (EMPD) is often difficult to diagnose and is frequently present for many years before treatment begins. Once diagnosed, some pathologists will place an EMPD diagnosis within an EMPD classification or stage. However, in some countries the diagnosis may be as straightforward as EMPD or invasive EMPD.

In 2002, Wilkinson and Brown proposed an extramammary Paget’s disease (EMPD) system of classification of either primary (cutaneous origin) or secondary (of non-cutaneous origin). The two EMPD classifications have three subtypes:

Primary EMPD (cutaneous origin)

       A) Intraepithelial cutaneous EMPD of the usual type

       B) Intraepithelial cutaneous EMPD with invasion

       C) Intraepithelial cutaneous EMPD as a manifestation of underlying adenocarcinoma of skin appendage

Secondary EMPD (of non-cutaneous origin)

       A) Anorectal origin

       B) Urothelial origin

       C) Other origin

Wilkinson later classified vulvar Paget disease with these classifications and subtypes:

Primary VPD (cutaneous)

Type 1a – Cutaneous vulvar non-invasive Paget’s disease

Type 1b – Cutaneous vulvar invasive disease: dermal invasion of Paget cells

Type 1c – Cutaneous vulvar disease as a manifestation of an underlying vulvar adenocarcinoma

Secondary VPD (non-cutaneous)

Type 2 – VPD originates from rectal or anal adenocarcinoma

Type 3 – VPD originates from urogenital neoplasia

In the United Kingdom, extramammary Paget’s disease (EMPD) is often classified into several subtypes:

Type 1a – Primary cutaneous extramammary Paget’s disease arising for apocrine glands within the epidermis (in situ) or underlying skin appendages.

Type 1b – Primary cutaneous extramammary Paget’s disease (15-25%) is associated with invasive Paget's disease or adenocarcinoma in situ.

Type 2 – Extramammary Paget’s disease originating from underlying anal or rectal adenocarcinoma.

Type 3 – Extramammary Paget’s disease originating from bladder adenocarcinoma.

Other physicians, in other regions, have used an EMPD classification system which has three levels:

• In situ in the epidermis (IE)

• Microinvasion into the papillary dermis (MI)

• Deep invasion into the reticular dermis (DI)

Perianal Paget’s Disease (PPD) is a subset of extramammary Paget's disease (EMPD), accounting for less than 6% of EMPD cases. It is often classified as:

Primary, of cutaneous origin

Secondary, result of pagetoid spread from anorectal or urogenital adenocarcinomas. The pagetoid spread refers to the proliferation of individual neoplastic cells upward into the epidermis.

In 2016 a group of Japanese doctors proposed a TNM Classification of Malignant Tumors (TNM) staging system for invasive EMPD. TNM describes the stage of a cancer using alphanumeric codes:

• Stage I, T1N0M0

• Stage II, T2N0M0

• Stage IIIa, anyTN1M0

• Stage IIIb, anyTN2M0

• Stage IV, anyTanyNM1

Other than stages II and IIIa, each stage had a statistically distinct survival curve for invasive EMPD.

• ‘T’ describes the size of the original (primary) tumor and whether it has invaded nearby tissue,

• ‘N’ describes nearby (regional) lymph nodes that are involved,

• ‘M’ describes distant metastasis (spread of cancer from one part of the body to another).

This invasive EMPD staging continues to be used in some areas of Asia but is not used everywhere.

All of the classifications mentioned here, sometimes called staging, may be used by some doctors. However, to date there is not an EMPD classification system universally accepted worldwide.

The content presented on this website, encompassing both textual material and visual media, serves educational and informational purposes aimed at aiding individuals affected by extramammary Paget’s disease (EMPD) and their families in comprehending the complexities associated with EMPD. It is imperative to note that the website is not designed to serve as a replacement for professional medical advice, diagnosis, or treatment. Furthermore, the website does not advocate for or endorse any specific treatments, tests, physicians, procedures, or products. Should you suspect that you are experiencing symptoms of EMPD, we strongly advise you to seek guidance from your healthcare provider.